In my U.S. Pat. Nos. 3,481,174 and 3,482,427, there is disclosed and claimed a sheet metal brake for bending metal or plastic sheets as are used in siding on homes and buildings.
This invention is directed to an improved sheet metal brake incorporating novel means for varying the force with which the workpiece is clamped prior to bending.
In accordance with the invention, a spring force for clamping the sheet to be bent is provided by an oval shaped spring member interposed between the member that engages the sheet and a clamping handle. Provision is made for changing the distance between the sides of the oval shaped spring to vary the spring force.